Hot top and seal signal device therefor



Feb. 22, 1966 .1. M. WETZIG m HOT TOP AND SEAL SIGNAL DEVICE THEREFOR Original Filed Aug. 9. 1960 IN VEN TOR. Joan M. WETZ/G 171 United States Patent "ice 3,236,492 HOT TOP AND SEAL SIGNAL DEVICE THEREFOR John M. Wetzig III, Maple Heights, Ohio, assignor to Oglehay Norton Company, Cleveland, Ohio, a corporation of Delaware Continuation of application Ser. No. 48,528, Aug. 9, 1960.

This application Feb. 1, 1963, Ser. No. 256,218 4 Claims. (Cl. 249202) This invention relates to a hot top and, more particularly, to a hot top seal signal device and to the combination of such device with the hot top construction.

This application is a continuation of my application Serial No. 48,528, filed August 9, 1960, now abandoned.

As is well known in the art, hot tops are used in conjunction with ingot molds in the pouring of molten metal as, for example, steel into the molds to produce ingots.

The purpose of the hot tops is to provide therein a reservoir of molten metal to feed the pipe or shrinkage cavity that tends to form in the solidifying ingot in the mold.

In teeming molten metal into the mold and hot top, particularly where the hot top is of the floating type, it is important that the pourer momentarily stops the stream of molten metal when the latter reaches approximately the bottom of the hot top in order to provide a time period so that the molten metal at the entrance to the clearance space between the inner wall surface of the mold and the outer surface of the hot top will solidify and provide a seal against molten metal flowing upwardly into the clearance space referred to. If this momentary stoppage of the pouring operation is not done at the proper time as the molten metal reaches approximately the bottom of the hot top the molten metal, when the pourer fills the hot top therewith, will flow upwardly into the clearance space between the mold and the hot top and such metal in said clearance space when it solidifies causes hot top stickers; that is, hot tops which cannot be readily stripped from the sinkhead when the ingot has solidified. Also if the molten metal rises so high in this clearance space as to run out over the top of the mold it may hang the ingot so the latter cannot sink down relative to the mold during the solidification of the ingot. This hanging of the ingot produces hanger cracks on the ingot surface and in the rolled product which are very detrimental and seriously increase the conditioning time and costs.

It has been difiicult for the pourer to know when the molten metal has reached approximately the bottom of the hot top, and this is especially so where the floating type of hot top extends a substantial distance into the mold.

The present invention rel-ates to a signal device which automatically will notify the pourer that the molten metal has reached approximately the bottom of the hot top and that the pourer should momentarily stop the pouring operation to allow the molten metal at the entrance to the clearance space between the hot top and the mold to solidify and to provide the desired seal against molten metal subsequently rising into said clearance space and producing hot top stickers when the hot tops are stripped from the sinkheads or hanger ingots as above explained.

An important object of the present invention is to provide a new and improved hot top signal device for the purposes described and which is reliable in operation.

Another object of the present invention is to provide such a hot top signal device which will flash when the molten metal reaches the bottom of the hot top but which is not subject to premature flashing due to sparks from the pouring operation.

3,236,492 Patented Feb. 22, 1966 Yet another object of the present invention is to provide a new and improved manner of supporting a flashtype signal device on a hot top which provides for convenient assembly of the flash device to the hot top, good visibility for the pourer, and reliable operation of the flash device.

Still anther object of the present invention is to provide a new and improved bottom ring structure for a hot top which includes means for receiving a flash device and for shielding the flash device from sparks.

A further object of the present invention is to provide a new and improved flash device which is adapted to operate in a nonoxidizing atmosphere and which is protected from premature flashing and which will be reliable in operation when applied to a hot top.

A still further object of the present invention is to provide a new and improved flash device having a novel structure and composition to provide for reliability of operation.

The detailed description of several embodiments of the invention which follows will bring out additional aspects and advantages of the invention and which embodiments are illustrated in the accompanying drawing forming a part of this specification and wherein:

FIG. 1 is an exploded perspective view of the signal device with the supporting member or strip coated with the flash composition shown above and about to be inserted into the protective envelope shown below;

FIG. 2 is a fragmentary view of a hot top, partly in perspective and partly in section, and illustrates a hot top equipped with the signal device of the invention and using a form of wiper strip wherein the lower portion of the signal device extends between the wiper strip and the bottom ring of the hot top and is accommodated in a relieved or oflset recess formed in the wiper strip;

FIG. 3 is a sectional view taken substantially on line 33 of FIG. 2 looking in the direction of the arrows but shows the hot top inserted in an ingot mold, a portion of which is shown in section;

FIG. 4 is a view similar to FIG. 2 but shows a different embodiment of the invention in that the signal device is used in combination with a hot top having a different form of wiper strip than is shown in FIG. 2 and wherein the signal device extends vertically through an opening or slot in the wiper strip and the lower end of the signal device lies exteriorly of the periphery of the bottom ring and below the wiper strip;

FIG. 5 is similar to FIG. 3 and is a sectional view taken substantially on line 55 of FIG. 4 looking in the direction of the arrows, and

FIG. 6 is a fragmentary sectional view also similar to FIG. 3 but illustrating a modified construction wherein the bottom ring is provided with a relieved ofiset or recess to receive the lower end of the signal device as distinguished from providing the wiper strip with a relieved ofl'set recess for such purpose.

The metal casing of the hot top shown in FIGS. 2, 4 and 6 is conventional and is formed of upper and lower parts 10 and 11 suitably secured together as will be well understood and may be of rectangular, octagonal, circular or other desired configuration. The upper part 10 of the casing has at its upper end an inwardly extending lip 12. The lower part 11 of the casing at its lower end has an inwardly extending lip 13 that is shorter than the lip 12. The lips 12 and 13 support a brick lining 14 of the hot top and this brick lining 14 may be covered on its inner surface with a slurry, a protective veneer, or a protective insert as the case may be and indicated schematically at 15.

When the hot top is prepared for a pouring operation the hot top while in inverted position has a refractory bottom ring 16 secured to its lower end by means of the conventional attaching clips 17 all as is well understood in the art. In FIGS. 2 and 3 the hot top is shown as equipped with a wiper strip 18 engaging the periphery of the bottom ring 16 and having a flange 19 which extends beneath and is in contact with the bottom of the bottom ring 16 and also having an outwardly flared upper flange portion 20 as will be well understood in the art.

The outwardly flared upper flange portion 20 of the wiper strip 18 is slotted as indicated at 21 to accommodate the attaching clips 17 which extend downwardly exteriorly of the wiper strip and beneath the same. It will be understood that when the hot top is lowered into the open upper end of a mold 22, as indicated in FIG. 3, the upper flared flange portion 20 of the wiper strip contacts the mold wall to provide a seal for a purpose well understood in the art.

The wiper strip 18 is formed of thin flexible sheet metal, and due to its inherent flexibility the signal device, later to be described, could be inserted between the wiper strip 18 and the periphery of the bottom ring 16 without altering the construction of the wiper strip. However, in order to facilitate inserting the signal device between the wiper strip and the periphery of the bottom ring 16 it is contemplated forming the wiper strip 18 with an outwardly offset or relieved recessed portion 23 as indicated in FIGS. 2 and 3. The offset portion 23 of the Wiper strip 18 may be provided with an opening 24 to facilitate the triggering of the flash of the signal device by the heat of or contact with the molten metal. During the pouring operation the wiper strip will shield the flash device from sparks to aid in preventing premature flashing of the device.

The signal device comprises a thin and somewhat flexible supporting member or strip 25 of material such as a strip of steel, wood, cardboard, or other suitable material. The strip 25 may vary in its dimensions but as an average indication of its size, it may be approximately ten inches in length, three-fourths of an inch in width and .028 of an inch in thickness. It will be understood that the dimensions of the strip 25 may vary for different sized hot tops with which the signal device is used.

It is proposed to coat the strip 25 with a suitable composition which, when subjected to heat as the molten metal in the mold rises and begins to enter the clearance space between the mold and hot top will flash with the result that the pourer is informed by the flash that he should momentarily halt the pouring operation for a suflicient time to allow the molten metal which has begun to rise in the clearance space to solidify and thus seal such space against further molten metal entering the same as the hot top is subsequently filled with the molten metal so as to avoid hot top stickers or hanger ingots. The flash composition 26 may be placed on one side only of the strip 25 or on several sides thereof or it may completely incrust the strip except for a limited length thereof at the upper end of the strip.

The flash composition includes an inflammable or flash material, examples of which are powdered aluminum or powdered magnesium or other similar materials. Also, the composition contains an oxidizing agent for the flash material that is responsive to heat and various chemical oxidizers can be used for this purpose as for instance potassium chlorate, sodium nitrate or other suitable oxidizers. The flash material and the oxidizing agent in the formation of the composition can be intermixed in equal percentages or in different suitable percentages such as, for example, 40% to 60% flash material and 40% to 60% oxidizing agent. The temperature of molten steel as it is poured into a mold equipped with a hot top usually ranges from 2700 F. to 2900 F. and such temperatures would be effective to trigger the flash signal device even though the percentages of the flash material and the oxidizing agent vary within the Percentage limits above stated.

The mixture of flash material and oxidizing agent is made into a paste by mixing therewith a suitable heat destructible binder formed of a liquid and a binding agent. One example of a suitable heat destructible binder is animal glue and Water. Another example is clear lacquer and further examples are lignin base products, gum paste, and other suitable pastes known to those skilled in the art.

The composition 26 in paste form can be applied to the strip 25 by painting the composition on one or more sides of the strip or by dipping the strip into the composition or in any other suitable way. The composition when applied to the strip may vary in thickness but preferably should be between K and 7&2 of an inch. After the composition 26 has been applied to the strip 25, the composition is then dried by any suitable means such as air blast, for instance. The strip 25 with the dried composition 26 thereon is then inserted into a suitable heat destructible protective envelope 27 to keep any sparks or heat occurring in the early part of the pouring operation from prematurely flashing the signal. The envelope 27 may be formed of paper, asbestos, cloth, canvas or other similar suitable heat destructable materials.

In the preparation of the hot top for a pouring operation when the bottom ring and wiper strip are secured to the hot top in the manner well known in the art, the signal device can be slipped into position in this instance between the wiper strip 18 and the periphery of the bottom ring 16 as indicated in FIGS. 2 and 3, and the lower end of the signal device may be supported in the offset recessed portion 23 of the wiper strip 18. Assuming the hot top has been prepared for a pouring operation and the signal device is positioned thereon, the hot top will be located in the open upper end of the mold 22 with the offset recessed portion 23 of the wiper strip and the signal device so located as to be readily observable by the pourer from the position he is in as he pours the molten metal into the mold. When the molten metal rises in the mold and begins to enter the clearance space between the hot top and mold the heat of or its contact with the molten metal acts on the composition 26 to cause it to flash and thus give the pourer an indication that he should momentarily stop the pouring operation sufliciently long to allow the molten metal in the clearance space between the hot top and the mold to solidify. The production of the flash of the signal device by the heat of or contact with the molten metal is facilitated :by the provision of the opening 24 in the offset recessed portion 23 of the wiper strip although the flash would occur without said opening since the wiper strip is relatively thin and is formed of heat conductive metal. At the completion of the pouring operation the heat of the molten metal in all likelihood will have destroyed the signal device after it has flashed since the envelope 27 and the binder of the composition 26 are both formed of heat destructible material or substance, while the strip 25 is relatively thin as previously pointed out.

In FIG. 6 of the drawing an arrangement is disclosed differing somewhat from that shown in FIGS. 2 and 3 and previously described. In FIG. 6 the wiper strip 18 is not provided with an offset or relieved recessed portion 23. In place of so providing the wiper strip 18 the refractory bottom ring 16 may be molded to have on its periphery an inwardly relieved recess 29. Then when the signal device is inserted between the wiper strip 18 and the periphery of the bottom ring 16, the lower end of the signal device can be accommodated in the recess 29 in the periphery of the bottom ring due to the flexibility of the signal device.

In FIGS. 4 and 5 of the drawing a different type of wiper strip is used on the hot top than that shown in FIGS. 2 and 3. The wiper strip shown in FIGS. 4 and 5 has a horizontal flange portion 30 which, in applying the wiper strip to the hot top, extends between the upper surface of the bottom ring 16 and the lower end of the casing of the hot top as will be well understood in the art. This wiper strip also has integral with the horizon tal flange 30 a flared or angularly disposed portion 31 the purpose of which is the same as the flared flange portion 20 of the previously described wiper strip. As in the previously described wiper strip, flared flange portion 31 is provided with slots 21 through which the attaching clips 17 extend. In addition, the wiper strip of FIGS. 4 and 5 is provided adjacent the junction of the flared flange portion 31 and the horizontal flange portion 30 thereof with a horizontal slot 32 of such size that the signal device can be inserted therethrough and held in position with the lower end outwardly of or engaging the periphery of the bottom ring as indicated in FIGS. 4 and 5.

Referring to FIG. 5 it will be seen that when the hot top is mounted in the open upper end of the mold 22 and the molten metal being poured into the mold begins to rise into the clearance spaced between the hot top and the mold the heat of or its contact with the molten metal functions to cause the device to flash and give the visual signal or indication to the pourer.

Although several embodiments of the invention have been illustrated and described herein it will be understood that the invention is susceptible of various modifications and adaptations within the scope of the appended claims.

Having described my invention, I claim:

1. A device for use on a hot top comprising, a refractory bottom ring adapted to be secured to the hot top, wiper strip means mounted on said bottom ring and including a vertical portion engaging and lying along the outer periphery of the bottom ring, a flash device responsive to the molten metal being poured into the mold when the molten metal begins to rise in the clearance space between the outer periphery of the hot top and the inner wall of the mold to produce a signaling flash and positioned between said vertical portion and the outer periphery of said ring, said vertical portion of said wiper strip having an opening therethrough adjacent said device to expose said flash device to the molten metal when the molten metal reaches the level of said opening and said device comprising a mass of material responsive to the heat of the molten metal to produce a flash signal when the level of the molten metal in the mold reaches a point adjacent the hot top, said mass of material consisting essentially of an oxidizing agent and an inflammable flash producing material, and a heat destructible protective envelope encompassing at least the exposed portion of said material when said device is in use.

2. A device for use on a hot top comprising, a refractory bottom ring adapted to be secured to the hot top, wiper strip means mounted on said bottom ring and including a vertical portion engaging and lying along the outer periphery of the bottom ring, a flash device responsive to the molten metal being poured into the mold when the molten metal begins to rise in the clearance space between the outer periphery of the hot top and the inner wall of the mold to produce a signaling flash and 6 positioned between said vertical portion and the outer periphery of said ring, said vertical portion of said wiper strip having an olfset portion providing a pocket for receiving said device and an opening through said otfset portion of said vertical portion to expose said device.

3. A device for use on a hot top comprising, a re fractory bottom ring adapted to be secured to the hot top, Wiper strip means mounted on said bottom ring and including a vertical portion engaging and lying along the outer periphery of the bottom ring, a flash device reponsive to the heat of the molten metal being poured into the mold when the molten metal begins to rise in the clearance space between the outer periphery of the hot top and inner wall of the mold to produce a signaling flash and positioned between said vertical portion and the outer periphery of said ring, said flash device including a mass of material consisting essentially of an oxidizing agent and an inflammable flash producing material and a heat destructible protective envelope encompassing at least the portion of said material adjacent the molten metal in said mold.

4. A device to be mounted at the lower end of a hot top for indicating the rise of molten metal in a mold having the hot top mounted at the top thereof comprising a mass of material to be supported on the hot top at the lower end thereof and responsive to the heat of the molten metal to produce a flash signal when the level of molten metal in the mold reaches a point adjacent to the lower end of the hot top, said mass of material consisting essentially of an oxidizing agent and of an inflammable flash producing material so as to provide for flashing thereof in the atmosphere around the hot top during the pouring of the molten metal, means for preventing premature flashing of said mass of material during the pouring of the molten metal including a heat destructible protective envelope encompassing at least the exposed portion of the material when the device is mounted on the hot top, and said device including a portion cooperable with a portion of the hot top for supporting the device in position on the hot top.

References Cited by the Examiner UNITED STATES PATENTS 2,530,454 11/1950 Fieser et al. l02-37.8 2,741,816 4/ 1956 White. 2,83 6,172 5/ 1958 Ginsburgh et al 10237.8 2,914,824 12/ 1959 Marcec. 3,027,612 4/1962 Ivory. 3,056,701 10/ 1962 Fritzen 10298 3,058,182 10/ 1962 Urmetz et al. 3,106,001 10/ 1963 Charman et al.

FOREIGN PATENTS 1,254,847 1/1961 France.

I. SPENCER OVERHOLSER, Primary Examiner.

MARCUS U. LYONS, MICHAEL V. BRINDISI,

Examiners. 

1. A DEVICE FOR USE ON A HOT TOP COMPRISING, A REFRACTORY BOTTOM RING ADAPTED TO BE SECURED TO THE HOT TOP, WIPER STRIP MEANS MOUTED ON SAID BOTTOM RING AND INCLUDING A VERTICAL PORTION ENGAGING AND LYING ALONG THE OUTER PERIPHERY OF THE BOTTOM RING, A FLASH DEVICE RESPONSIVE TO THE MOLTEN METAL BEING POURED INTO THE MOLD WHEN THE MOLTEN METAL BEGINS TO RISE IN THE CLEARANCE SPACE BETWEEN THE OUTER PERIPHERY OF THE HOT TOP AND THE INNER WALL OF THE MOLD TO PRODUCE A SIGNALING FLASH AND POSITIONED BETWEEN SAID VERTICAL PORTION AND THE OUTER PERIPHERY OF SAID RING, SAID VERTICAL PORTION OF SAID WIPER STRIP HAVING AN OPENING THERETHROUGH ADJA- 